Conventionally, an automated embroidering machine is used for mechanical embroidery. Japanese Patent No.2596093 discloses an embroidering simulation apparatus that displays a stitch image according to embroidering data to form an embroidery pattern, and that changes brightness of the stitch image of a thread that connects embroidering points, between embroidering points so as to make the stitches brighter at the central portion thereof than at both the end portions. It is also described that stitches can be displayed one by one with a slightly different brightness, and a stitch direction can be shown without giving a sense of incongruity, by adding a predetermined noise that differs from a stitch datum to a stitch datum so that the stitch direction is seen after the display.
Microscopically, embroidery has a stereoscopic structure that puts a thread on the surface of cloth as a stitch. Microscopically, embroidery has a characteristic texture obtained by assembling stitches that form a pattern as a flat image. Japanese Patent No.2596093 uses a method of showing the central portion of a stitch image between embroidering points brighter than the end portions thereof in order to improve the texture of the completed embroidery. However, even when carrying out an embroidering simulation with this method, the obtained stereoscopic image or texture is not always satisfactory, so that the simulation image does not have a quality that can be used as a sample that can be substituted for a real material.